//
// experimental/co_spawn.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2021-2022 Klemens D. Morgenstern
//                         (klemens dot morgenstern at gmx dot net)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef ASIO_EXPERIMENTAL_CO_SPAWN_HPP
#define ASIO_EXPERIMENTAL_CO_SPAWN_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/config.hpp"
#include <utility>
#include "asio/compose.hpp"
#include "asio/detail/type_traits.hpp"
#include "asio/experimental/coro.hpp"
#include "asio/experimental/deferred.hpp"
#include "asio/experimental/prepend.hpp"
#include "asio/redirect_error.hpp"

#include "asio/detail/push_options.hpp"

namespace asio {
    namespace experimental {
        namespace detail {

            template<typename T, typename U, typename Executor>
            struct coro_spawn_op {
                coro <T, U, Executor> c;

                void operator()(auto &self) {
                    auto op = c.async_resume(deferred);
                    std::move(op)((prepend)(std::move(self), 0));
                }

                void operator()(auto &self, int, auto... res) {
                    self.complete(std::move(res)...);
                }
            };

        } // namespace detail

/// Spawn a resumable coroutine.
/**
 * This function spawns the coroutine for execution on its executor. It binds
 * the lifetime of the coroutine to the executor.
 *
 * @param c The coroutine
 *
 * @param token The completion token
 *
 * @returns Implementation defined
 */
        template<typename T, typename Executor, typename CompletionToken>
        ASIO_INITFN_AUTO_RESULT_TYPE(
                CompletionToken,
        void(std::exception_ptr, T
        ))
        co_spawn(coro<void, T, Executor>
        c,
        CompletionToken &&token
        ) {
        auto exec = c.get_executor();
        return
        async_compose<CompletionToken, void(std::exception_ptr, T)>(
                detail::coro_spawn_op<void, T, Executor>{std::move(c)},
                token, exec
        );
    }

/// Spawn a resumable coroutine.
/**
 * This function spawns the coroutine for execution on its executor. It binds
 * the lifetime of the coroutine to the executor.
 *
 * @param c The coroutine
 *
 * @param token The completion token
 *
 * @returns Implementation defined
 */
    template<typename T, typename Executor, typename CompletionToken>
    ASIO_INITFN_AUTO_RESULT_TYPE(
            CompletionToken,
    void(std::exception_ptr, T
    ))
    co_spawn(coro<void(), T, Executor>
    c,
    CompletionToken &&token
    ) {
    auto exec = c.get_executor();
    return
    async_compose<CompletionToken, void(std::exception_ptr, T)>(
            detail::coro_spawn_op<void(), T, Executor>{std::move(c)},
            token, exec
    );
}

/// Spawn a resumable coroutine.
/**
 * This function spawns the coroutine for execution on its executor. It binds
 * the lifetime of the coroutine to the executor.
 *
 * @param c The coroutine
 *
 * @param token The completion token
 *
 * @returns Implementation defined
 */
template<typename T, typename Executor, typename CompletionToken>
ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken,
void(T)
)
co_spawn(coro<void() noexcept, T, Executor>
c,
CompletionToken &&token
)
{
auto exec = c.get_executor();
return
async_compose<CompletionToken, void(T)>(
        detail::coro_spawn_op<void() noexcept, T, Executor>{std::move(c)},
        token, exec
);
}

/// Spawn a resumable coroutine.
/**
 * This function spawns the coroutine for execution on its executor. It binds
 * the lifetime of the coroutine to the executor.
 *
 * @param c The coroutine
 *
 * @param token The completion token
 *
 * @returns Implementation defined
 */
template<typename Executor, typename CompletionToken>
ASIO_INITFN_AUTO_RESULT_TYPE(
        CompletionToken,
void(std::exception_ptr)
)
co_spawn(coro<void, void, Executor>
c,
CompletionToken &&token
)
{
auto exec = c.get_executor();
return
async_compose<CompletionToken, void(std::exception_ptr)>(
        detail::coro_spawn_op<void, void, Executor>{std::move(c)},
        token, exec
);
}

/// Spawn a resumable coroutine.
/**
 * This function spawns the coroutine for execution on its executor. It binds
 * the lifetime of the coroutine to the executor.
 *
 * @param c The coroutine
 *
 * @param token The completion token
 *
 * @returns Implementation defined
 */
template<typename Executor, typename CompletionToken>
ASIO_INITFN_AUTO_RESULT_TYPE(
        CompletionToken,
void(std::exception_ptr)
)
co_spawn(coro<void(), void, Executor>
c,
CompletionToken &&token
)
{
auto exec = c.get_executor();
return
async_compose<CompletionToken, void(std::exception_ptr)>(
        detail::coro_spawn_op<void(), void, Executor>{std::move(c)},
        token, exec
);
}

/// Spawn a resumable coroutine.
/**
 * This function spawns the coroutine for execution on its executor. It binds
 * the lifetime of the coroutine to the executor.
 *
 * @param c The coroutine
 *
 * @param token The completion token
 *
 * @returns Implementation defined
 */
template<typename Executor, typename CompletionToken>
ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken,
void())
co_spawn(coro<void() noexcept, void, Executor>
c,
CompletionToken &&token
)
{
auto exec = c.get_executor();
return
async_compose<CompletionToken, void()>(
        detail::coro_spawn_op<void() noexcept, void, Executor>{std::move(c)},
        token, exec
);
}

} // namespace detail
} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif //ASIO_EXPERIMENTAL_CO_SPAWN_HPP
